1. Field
The present inventive concept relates generally to medical imaging and analysis; and, more particularly to a system and method to enhance clinical decision making capability within the context of an image reporting and data system (IRADS) for medical diagnosis. The present inventive concept provides a confidence level indication (CLI) for a computer-assisted diagnosis (CAD) system that is programmed to minimize the deviations in recommended clinical actions due to the biases of a group or individual in interpreting the rules of the system.
2. Discussion of Related Art
Each year, over 1,300,000 breast biopsies are performed in the United States and over 4,500,000 breast biopsies are performed worldwide. Of these biopsies, 80% have benign findings. Breast biopsies are traumatic experiences that expose patients to clinical risk, are uncomfortable, and are costly.
A trained medical professional such as a radiologist will generally attempt to identify and classify regions of suspicion within a medical image either manually or by using computer software. The radiologist may then manually characterize each region of suspicion in accordance with a relevant grading system. For example, suspicious regions of interest within the breast may be characterized according to Breast Imaging Reporting and Data Systems (BI-RADS) guidelines. BI-RADS is a widely-accepted risk assessment and quality assurance tool used by radiologists for diagnosing breast cancer using mammography, ultrasound, or MRI. The classification assigned to each region of suspicion may dictate the future course of action. For example, if the region of suspicion is classified as likely malignant, then a biopsy may be ordered. If the region of suspicion is classified as normal, then no further action may be taken. If, however, the region of suspicion is classified as probably benign, then the course of action may be to repeat the test in six months to look for any changes. The BI-RADS reporting methodology includes a standard lexicon and structure for reporting purposes which enables radiologists to provide a succinct review of image based findings and to communicate the results to the referring physician in a clear and consistent fashion with a final assessment and a specific course of action. Structured reporting also helps accelerate report turnaround time (TAT), simplify documentation for billing and regulatory compliance, and ease the process of data extraction for utilization review, quality assurance, and research. Through medical audit and outcome monitoring, the system provides important mechanisms for peer review and quality assurance data to improve the quality of patient care. Results compiled in a standardized manner permit the maintenance and collection analysis of demographic and outcome data.
The success of BI-RADS since its inception for mammography in 1993 has spurred the introduction of many more similar checklist-based systems for various medical image reporting and data systems. A partial list of similar reporting and data systems include Prostate Imaging-Reporting and Data System (PI-RADS), Thyroid Imaging Reporting and Data System (TI-RADS), Liver Imaging Reporting and Data System (LI-RADS), and Lung-RADS for prostate, thyroid, liver and lung cancer diagnosis, respectively.
The basic BI-RADS Assessment Categories are:
1: Negative,
2: Benign,
3: Probably benign,
4. Suspicious, and
5: Highly suggestive of malignancy.
There is also a category 0 (BI-RADS 0) and a category 6 (BI-RADS 6). A BI-RADS 0 indicates an incomplete classification which warrants either an effort to ascertain prior imaging for comparison or to call the patient back for additional views, higher quality films or additional imaging modalities. A BI-RADS 6 indicates a proven malignancy previously proven by biopsy.
The BI-RADS 4 classification is frequently divided into sub-categories of:
4A: low suspicion for malignancy,
4B: moderate suspicion for malignancy, and
4C: highly suspicious for malignancy.
The recommended patient management provided by the BI-RADS system is: if the region of interest is classified as suspicious or highly suspicious, i.e., BI-RADS 4 or BI-RADS 5, then a biopsy should be ordered. If the region of suspicion is classified as normal or benign, i.e., BI-RADS 1 or BI-RADS 2, then no further action may be taken. If, however, the region of suspicion is classified as probably benign, i.e., BI-RADS 3, then the recommendation is a 6-month follow-up to look for any changes. The BI-RADS score is a statistic that is correlated with malignancy and not a deterministic measure of malignancy. It has been shown that category 3 (less than 2 percent risk of malignancy) or category 4 (probability of cancer, ranging from 3 percent to 94 percent) lesions are considered different degrees of malignant breast lesions. This is especially true for hyperplastic nodules in category 3, which are considered to be uncertain ones. Such lesions do not have obvious characteristics of benign lesions, but they are still considered subjectively as category 3 lesions. There are 1-2 non-benign characteristics of category 4 lesions, but the American College of Radiology does not provide any detailed guidance. This leads to poor inter-observer consistency in classification with resulting discrepancies from the ideal use of the BI-RADS system. In addition, Category 4a typically consists of 90% to 98% benign lesions, 4b consists of 50% to 90% benign lesions and 4c consists of 5% to 50% benign lesions and BI-RADS 5 has 0% to 5% benign lesions but all must go to biopsy. Therefore, as many as 80% of the biopsies performed on the patients with a category BI-RADS 4 or BI-RADS 5 are found to be benign.
Computer-aided diagnosis (CAD) systems have the potential to improve radiologists' diagnostic performance. However, in practice radiologists have difficulty knowing when to accept or decline the recommendations made by a CAD system.
It is with these observations in mind, among others, that various aspects of the present inventive concept were conceived and developed.